ruby/lib/net/imap/authenticators/digest_md5.rb
nicholas a. evans 2fc91da86c
[ruby/net-imap] Clean up authenticators rdoc
Added RFC links to all SASL mechanism specifications.

53ff4b0c09
2021-05-06 15:20:34 +09:00

111 lines
3.2 KiB
Ruby

# frozen_string_literal: true
require "digest/md5"
require "strscan"
# Net::IMAP authenticator for the "`DIGEST-MD5`" SASL mechanism type, specified
# in RFC2831(https://tools.ietf.org/html/rfc2831). See Net::IMAP#authenticate.
#
# == Deprecated
#
# "+DIGEST-MD5+" has been deprecated by
# {RFC6331}[https://tools.ietf.org/html/rfc6331] and should not be relied on for
# security. It is included for compatibility with existing servers.
class Net::IMAP::DigestMD5Authenticator
def process(challenge)
case @stage
when STAGE_ONE
@stage = STAGE_TWO
sparams = {}
c = StringScanner.new(challenge)
while c.scan(/(?:\s*,)?\s*(\w+)=("(?:[^\\"]+|\\.)*"|[^,]+)\s*/)
k, v = c[1], c[2]
if v =~ /^"(.*)"$/
v = $1
if v =~ /,/
v = v.split(',')
end
end
sparams[k] = v
end
raise DataFormatError, "Bad Challenge: '#{challenge}'" unless c.rest.size == 0
raise Error, "Server does not support auth (qop = #{sparams['qop'].join(',')})" unless sparams['qop'].include?("auth")
response = {
:nonce => sparams['nonce'],
:username => @user,
:realm => sparams['realm'],
:cnonce => Digest::MD5.hexdigest("%.15f:%.15f:%d" % [Time.now.to_f, rand, Process.pid.to_s]),
:'digest-uri' => 'imap/' + sparams['realm'],
:qop => 'auth',
:maxbuf => 65535,
:nc => "%08d" % nc(sparams['nonce']),
:charset => sparams['charset'],
}
response[:authzid] = @authname unless @authname.nil?
# now, the real thing
a0 = Digest::MD5.digest( [ response.values_at(:username, :realm), @password ].join(':') )
a1 = [ a0, response.values_at(:nonce,:cnonce) ].join(':')
a1 << ':' + response[:authzid] unless response[:authzid].nil?
a2 = "AUTHENTICATE:" + response[:'digest-uri']
a2 << ":00000000000000000000000000000000" if response[:qop] and response[:qop] =~ /^auth-(?:conf|int)$/
response[:response] = Digest::MD5.hexdigest(
[
Digest::MD5.hexdigest(a1),
response.values_at(:nonce, :nc, :cnonce, :qop),
Digest::MD5.hexdigest(a2)
].join(':')
)
return response.keys.map {|key| qdval(key.to_s, response[key]) }.join(',')
when STAGE_TWO
@stage = nil
# if at the second stage, return an empty string
if challenge =~ /rspauth=/
return ''
else
raise ResponseParseError, challenge
end
else
raise ResponseParseError, challenge
end
end
def initialize(user, password, authname = nil)
@user, @password, @authname = user, password, authname
@nc, @stage = {}, STAGE_ONE
end
private
STAGE_ONE = :stage_one
STAGE_TWO = :stage_two
def nc(nonce)
if @nc.has_key? nonce
@nc[nonce] = @nc[nonce] + 1
else
@nc[nonce] = 1
end
return @nc[nonce]
end
# some responses need quoting
def qdval(k, v)
return if k.nil? or v.nil?
if %w"username authzid realm nonce cnonce digest-uri qop".include? k
v.gsub!(/([\\"])/, "\\\1")
return '%s="%s"' % [k, v]
else
return '%s=%s' % [k, v]
end
end
Net::IMAP.add_authenticator "DIGEST-MD5", self
end